EP1395375A1

EP1395375A1 - Device for disassembling rolling mill cylinders

Info

Publication number: EP1395375A1
Application number: EP02740798A
Authority: EP
Inventors: Germain Le Viavant
Original assignee: VAI Clecim SA
Current assignee: Clecim SAS
Priority date: 2001-05-18
Filing date: 2002-05-17
Publication date: 2004-03-10
Also published as: WO2002094465A1; US20040144150A1; FR2824764A1; FR2824764B1; CN1463208A; RU2003136282A; KR20030022865A

Abstract

The invention relates to a device for disassembling rolling mill cylinders that move by translation and rest, successively, on internal (5) and external (55) rails on which the chock (3) support rollers (7) move. According to the invention, each internal rail (5) comprises two sections (51, 52) which are mounted respectively to slide on the two columns (10, 100) of the roll housing (1) between a recoiled rolling position and a forward disassembly position. For the latter position, the two sections (51, 52) are moved closer together, the internal ends thereof (53', 54') being separated by a clearance (e). Each chock (3) is fitted with rollers (72, 72') which are spaced out from one another by a distance (d) that is greater than said clearance (e). In this way, the cylinders rest successively on said sections (51, 52) during disassembly and reassembly.

Description

Device for dismantling the rolls of a rolling mill

The subject of the invention is an installation for replacing rolls, in particular working rolls, in a rolling stand. It is known that a rolling mill comprises, inside a cage, at least two cylinders rotatably mounted around parallel axes and placed in a substantially vertical plane. “Duo” cages, for example, have only two cylinders between which the product to be rolled passes. In the so-called "Quarto" cages, the product to be rolled passes between two relatively small diameter working cylinders and is supported directly on two support cylinders. In the so-called “Sexto” cages, intermediate cylinders are interposed between each working cylinder and the corresponding support cylinder. But other types of rolling mills are also known, for example of the “Sendzimir” type which include a large number of rolls or the so-called “Z-High” rolling mills in which each working roll is associated with lateral support rollers, the 'set being placed in an insert.

The working rolls, which are in contact with the product, wear out fairly quickly. Furthermore, their diameter must be able to be adapted to the nature and the thickness of the product to be laminated as well as, in certain cases, to the surface state to be obtained. These cylinders must therefore be replaced periodically.

It is the same, in "Sexto" rolling mills, intermediate rolls or inserts, in "Z-High" rolling mills.

Previously, the cylinders were disassembled cantilevered by a system called load-bearing bars, comprising a cylinder support member balanced by a counterweight.

However, for several years, devices have been developed intended to reduce the intervention time, the risks of people or equipment and making it possible to automate the sequences. It is known that, in general, each cylinder is rotatably mounted, at its ends, on centering bearings housed in two chocks on which support means for adjusting the height of the cylinders, each chock being slidably mounted along guide faces parallel to a clamping plane passing through the axes of the working rolls.

To allow the withdrawal and introduction of the cylinders, chocks are generally provided with rollers which roll on rails extending between the two columns of the cage, parallel to the axes of the cylinders.

In some cases, to disassemble the two cylinders, the upper cylinder is made to rest on the chocks of the lower cylinder which roll on two rails placed on either side of the clamping plane.

However, the technique of continuous rolling is used more and more which requires changing the rolls while keeping the strip engaged between the two working rolls. In this case, two pairs of cylinder dismantling rails are used, placed respectively at two levels for which the cylinders are spaced from the strip.

In all cases, the cylinders to be dismantled are therefore removed from the cage by displacement parallel to their axis and transferred to an external device comprising rails respectively placed in the extension of the rails in the cage and a carriage fitted with motorized extractor devices which allow the exit of the cylinders from the cage or, conversely, the introduction of the new cylinders. To speed up operations, two carriages are often used slidingly mounted on rails parallel to the direction of travel and arranged on a lateral frame, one of the carriages comprising an empty box for receiving used cylinders and the other carriage carrying new cylinders which can be introduced into the cage after the extraction of the worn cylinders. When the disassembly is carried out with the band engaged, each carriage comprises two pairs of rails which are placed in the extension of the two pairs of rails of the cage.

Even if the working cylinders have a fairly small diameter, their weight remains significant and the dismantling rails must therefore have sufficient dimensions to support them. These devices are therefore relatively bulky and must, however, extend on either side of the clamping plane and close to it since they support the chocks of each cylinder to be dismantled. However, generally, the inner zone of the cage, at the level of the working rolls, is already cluttered by devices of all kinds, such as band engagement tables, spray bars, devices intended to protect the cylinders in the event of rupture of bands, etc. Even in the case of a new cage, it is difficult, in addition to these essential devices, to house dismantling rails in a reduced space. Admittedly, it is possible to use removable rails which are not placed in the cage until the cylinders are replaced, but the time for installing and dismantling the rails increases the duration of the operation, which is contrary to goal sought.

On the other hand, one cannot either reduce the dimensions of the rails without dangerously weakening them.

The present invention makes it possible to solve all of these problems thanks to a replacement device which, without dismantling the rails, makes it possible to completely free the space between the columns of the cage, during the rolling operations.

The invention therefore generally relates to a device for dismantling rolls for a rolling mill in which the rolls are moved in translation, parallel to their axis, between a rolling position between the columns of the cage and a dismounting position. separated from the outside of the cage, bearing, successively, on at least one pair of internal rails extending respectively, on each side of the clamping plane, between the corresponding uprights of each column and extended by at least one pair of external rails extending outside the cage, at least on a dismantling side, the two chocks of the cylinder to be dismantled being provided with movable support members on said internal and external rails.

According to the invention, on each side of the clamping plane, each internal rail consists of two sections, each extending over a limited length, between two ends, respectively internal and external and mounted sliding, respectively, on the two columns of the stand, parallel to the axis of the cylinder and the rolling mill comprises means for controlling the sliding of the two sections of each internal rail between a rolling position for which each section extends substantially over the width of the corresponding column and a cylinder disassembly position for which the two sections are advanced towards one another, in the interval between the two columns, the internal ends of said sections being separated by a free space. In addition, each movable support member of a chock is spaced from the median plane thereof a distance greater than the distance between said median plane and the end of the corresponding rail section when the latter is in the rolling position and at least the chock holding the end of the cylinder opposite to the dismantling side is equipped, on each side of the clamping plane, with two movable support members spaced from one another, on either side of the median plane of the chock, a distance greater than the length of the existing free space, in the disassembly position of the cylinder, between the internal ends, facing each other, of the two corresponding internal rail sections.

In a preferred embodiment, the two chocks of the cylinder to be dismantled are each provided, on each side of the clamping plane, with a pair of movable support members spaced apart from each other by a greater distance to the length of the corresponding rail section.

These support members, preferably made up of rollers, are each mounted at the end of an arm fixed on the corresponding side of the chock and extend axially towards the outside of the chock. , so as to place the support member at the desired distance from the median plane of the chock.

On the other hand, it is advantageous that the sections of rails mounted on the same column of the cage, on either side of the clamping plane, are interconnected and associated with a single means of controlling the simultaneous sliding of said sections , from the rolling position to the dismantling position and vice versa.

In the case where the two working cylinders are dismantled simultaneously by resting the upper cylinder on the lower cylinder, the device comprises two pairs of rail sections mounted respectively on the two columns of the cage at the same dismantling level, so as to form two internal rails, on either side of the clamping plane.

In another more sophisticated embodiment, allowing disassembly of the engaged strip, the device comprises four pairs of sections rails mounted respectively, at two levels of disassembly, on the two columns of the cage, so as to form, at each level, two internal rails extending respectively on either side of the clamping plane. Such a device therefore makes it possible, while keeping the strip engaged, to translate, separately or simultaneously, the two working rolls by keeping them apart on either side of the rolling plane. A similar arrangement makes it possible, in a "Z-High" type rolling mill, to disassemble and replace, separately or simultaneously, the inserts each comprising a working cylinder and two lateral support rollers. Other arrangements are however possible and one could, for example in a "Sexto" rolling mill, use eight pairs of rail sections mounted respectively at four levels for dismantling the working rolls and the intermediate rolls.

The invention also covers the process for implementing such a dismantling device. According to the invention, after having placed the cylinders at their disassembly level, the sections of rails placed on one side before disassembly are first ordered to slide towards the inside of the cage, and a Replacement carriage fitted with external rails which are placed in the extension of the sections of internal rails thus advanced. We then control the translation of the cylinder to be replaced which rests on the sections of internal rails and we then advance, towards the inside of the cage, the sections of rails mounted on the rear column. The rear chock placed on the side opposite to the carriage thus bears, successively on the rear sections then on the front sections by its two separated support members, crossing the free space between said sections. By reverse operations, it is possible to introduce a replacement cylinder into the cage then to slide the sections of internal rails towards the outside of the cage in order to replace them in the rolling position, each at a column, the cylinder chocks can then be moved vertically to adjust the spacing between the working rolls.

For the implementation of the invention, it is particularly advantageous for the rolling mill to be equipped with C hydraulic blocks comprising, on either side of the rolling plane, two projecting parts at the ends of which are provided with lateral guide faces of the working chocks, these being provided with bearing ears offset towards the rolling plane and engaging in a central notch of each hydraulic block, formed between the projecting parts of that -this. Indeed, the rail sections mounted on each column can, in this case, be arranged along the ends of the projecting parts of the hydraulic blocks and each rail is housed in a notch formed on a part of the height of the corresponding lateral side of the chock while retaining, on said lateral side and on the end of the projecting part, guide faces sliding one on the other and having a height compatible with the possibilities of level adjustment of the chock.

Each rail section is thus slidably mounted axially between the end of the projecting part of the hydraulic block and the bottom of the notch formed on the lateral side of the chock, said bottom and the corresponding face of the rail being provided with plates. wear which slide one on the other, on the one hand in the axial direction during displacements of the rail section and, on the other hand, in the vertical direction when adjusting the level of the chock, so as to constitute an additional means of lateral support of the chock.

The invention also covers other advantageous arrangements mentioned in the claims.

However, the invention will be better understood from the following description of a particular embodiment, given by way of example and shown in the accompanying drawings.

Figure 1 shows, in elevation, the conventional arrangement of a rolling stand equipped with various ancillary members.

Figure 2 is a top view of a rolling mill equipped with the device according to the invention, in section along the rolling plane P-i.

FIG. 3 is a view in elevation and partially in section along the line III-III of FIG. 2. FIG. 4 is a view in section along the line IV-IV of FIG. 3.

FIG. 5 schematically shows the sequence for dismantling a cylinder. In FIG. 1, there is shown, in elevation, the assembly of a conventional rolling mill of the quarto type comprising a cage 1, two working rolls respectively lower 2 and upper 2 ', and two support rolls 15, 15'. Each cylinder 2, 2 ', 15, 15' is rotatably mounted, at its ends, on two bearings housed in chocks 3, 3 ', 16, 16' and centered on a median plane Q orthogonal to the axis of the cylinder.

As usual, the holding cage 1 comprises two spaced apart columns 10 each comprising a window 11 bounded by two uprights 12a, 12b of the column and in which the chocks of the cylinders are threaded which are held laterally by sliding guide faces 13 parallel to a clamping plane P ₂ passing substantially through the axes of the cylinders, so as to allow the height adjustment of the cylinders under the action of clamping means 14 bearing on the columns 10 of the cage and means (not shown) for adjusting the cylinder levels. Since the working rolls 2, 2 ′ have a relatively small diameter, the guide faces 13 of their chocks 3, 3 ′ are formed on solid parts or “hydraulic blocks” 4 which project into the interior of the window 1 1 and carry, in modern cages, hydraulic cylinders for bending the working cylinders 2, 2 '. As shown in Figure 1, a rolling stand is usually equipped with a number of ancillary members which are placed at the level of the two working rolls, close to the latter, on either side of the plane of the strip to be laminated M.

For example, such a rolling stand may comprise, on each side of the clamping plane P ₂ , an engagement table A, spray bars B placed as close as possible to the cylinders 2, 2 ', a tensiometer roller C , a bar feed roller D mounted on a device which makes it possible to move it towards or away from the strip, as well as guard plates E intended to protect the cylinders in the event of a strip break. All these ancillary members and, in particular, the spray bars B and the guard plates E must be placed near the working cylinders 2, 2 'in a reduced space vertically limited by the chocks 16, 16' of the cylinders of support 15, 15 'and laterally by the two columns 10, 100 of the cage. It is therefore difficult to place in addition, in this space, rails allowing the disassembly of the cylinders.

The invention makes it possible to solve this problem thanks to an original arrangement of the dismantling rails shown in FIGS. 2, 3 and 4. In the embodiment shown in FIG. 1, the chocks of the working rolls are of the conventional type comprising two support ears placed in the central part of the chock and on which act, in opposite directions, camber cylinders, respectively positive and negative, placed on each side of the ear. Each hydraulic block therefore has an E-shape comprising a central support part for the positive camber cylinders and two end parts, respectively lower and upper, for supporting the negative camber cylinders.

The invention can be applied to this type of cage. However, it is particularly advantageous to use the arrangement described in French patent n ° 2786415 of the same company, in which the ears of the chocks are offset towards the rolling plane, each hydraulic block having a C shape comprising only two parts projecting guide of the working chocks 3, 3 ', in which are housed the camber cylinders, respectively positive and negative, of the cylinders 2, 2'. This preferred embodiment has therefore been shown in the figures.

2, 3 and 4.

According to the arrangement described in the preceding patent n ° 2786415, the central part of the hydraulic block is eliminated, each positive cambering cylinder of a chock bearing on the projecting part of the hydraulic block placed on the other side of the rolling plane and in front therefore, cross this one. For this, as shown in FIG. 2, the support ears of each chock 3 have a stage profile comprising a projecting part 31 for supporting the positive and negative bending cylinders of the cylinder 2 considered and a free space 32 for passage of the positive camber cylinder 2 'placed on the other side of the rolling plane. In addition, the support parts 31 a, 31 b placed on either side of the clamping plane P ₂ are offset, respectively, in front and behind the median plane Q of the chock, so as to ensure the centering of the result of the applied forces. As explained in patent No. 2786415, such an arrangement has the particular advantage of reducing the overall height of the hydraulic blocks and chocks, because the bearing ears of the two chocks can be placed near the plane of rolling, in the central notch of each C-shaped hydraulic block

In conventional disassembly devices, the rollers for chocks are often mounted at the end of the bearing lugs and the disassembly rails must therefore be placed between the projecting parts of the hydraulic blocks carrying the camber cylinders. The assembly is quite bulky and can hardly be accommodated between the uprights of each column of the cage, in the case, for example, of the modernization of an existing rolling mill.

The arrangement with C block described in the preceding patent n ° 2786415 is, on the other hand, particularly well suited to the installation of dismantling rails. Indeed, since the support ears of each chock are offset from the side of the rolling plane, there is the entire remaining height of the chock to provide the lateral retaining faces thereof and it is thus possible placing guide rails over part of the height of the projecting part of the hydraulic block, while retaining the guide height necessary for adjusting the level of the cylinder.

Such an arrangement is shown, in particular, in FIG. 3 which is an elevation view of the hydraulic blocks and chocks, partially in section along the line III-III in FIG. 2.

As already indicated, it is necessary to periodically replace the working rolls due to their wear and this must therefore be taken into account when determining the possibilities of height adjustment of the chocks. Figure 3 shows, by way of example, worn cylinders on its left side and new cylinders on its right side.

As indicated, the two working cylinders 2, 2 'are carried, at each end, by chocks 3, 30, 3', 30 ', which are slidably mounted vertically between two fixed hydraulic blocks 4a, 4b, respectively, on the two uprights 12a, 12b of each column 10, 100 and each hydraulic block 4 has two projecting parts, respectively lower 41 and upper 41 ', on either side of a central notch 42 into which the ears 31, 31' of the two chocks 3, 3 'penetrate. In these projecting parts 41, 41 ′ are housed the bending cylinders, respectively positive 43 and negative 44 of the cylinders. Due to the C-shape of the hydraulic block, the positive camber cylinder 43 of the lower chock 3 is placed in the upper part 41 'of the hydraulic block 4 and therefore crosses the rolling plane Pi to bear on the ear 31 of the lower chock 3 passing through a recess 32 of the upper chock 3 '. Due to the offset, towards the rolling plane Pi, of the ears 31, the lateral guide faces of the chocks, formed at the ends of the projecting parts 41, 41 ′, can extend practically over the entire height of the chock. This particular arrangement facilitates the positioning of the support rails 5, 5 ′ inside the hydraulic blocks.

In fact, as shown in FIG. 3, the support rails 5, 5 ′ can be placed at the level of the protruding parts 41, 41 ′ for guiding the chocks 3, 3 ′, the rollers 7 being mounted directly on the lateral sides 34 of the chocks and not, as before, at the ends of the support ears.

If we consider, for example, the upper chock 3 ', we see in Figure 3 that due to the relatively large height of the lateral side 34 of the chock 3, it is possible to spare a notch 33 in which can be accommodated a support rail 5 ′, while retaining a sufficient height for guiding the chock, along the remaining part of the lateral side 34 which is provided with a wear plate 35 In this way, the support rail 5 ', the height hi of which is determined so as to give it the necessary resistance, extends along the end 43 of the projecting part 41' of the hydraulic block 4, leaving a side 45 of lateral guide of the chock, in contact with the guide face 35 of the chock and extending over a height h ₂ compatible with the need to maintain the chock laterally over the entire height of adjustment level, the two guide faces in contact 35, 45 being provided with wear plates.

The lower chock 3 is produced in a similar manner taking into account, however, the mounting of the rollers 7 for supporting the chocks which, as usually have to roll on the rails 5, 5 'for disassembly of the cylinders and are therefore placed above the latter.

For example, in Figure 3 which shows the cylinders in their disassembly positions, spaced on either side of the strip to be laminated M we see that the guide faces 45 of the hydraulic block and 35 of the chock are at the same level and extend over the entire height h2, the rollers 7 being located just above the upper level of the support rails 5, 5 '.

Therefore, for the upper chock 3 ', the rollers 7' can be placed at the upper part of the lateral side 34, the lower part of which forms the guide face 35.

On the other hand, for the lower chock 3, the rollers 7 must be placed above the notch 33 and the lateral guide faces 35 are formed at the same level of the chock 3, between the ear of support 31 and notch 33. In addition, according to the invention, each support rail 5 consists of two sections mounted respectively on the two columns 10 and 100 of the cage, as shown in Figure 2. Each cylinder is therefore associated with two pairs of rail sections placed respectively on each column 10, 100, on either side of the clamping plane P ₂ . Thus, as shown in FIG. 2, the lower working cylinder 2 carried, at its ends, by two chocks, respectively front 3 and rear 30, guided respectively in the two columns 10, 100 of the cage, is associated with two pairs sections of rails, respectively 51 a, 51 b carried by the front column 10 and 52a, 52b carried by the rear column 100. Since the disassembly can be done with the band engaged, the upper cylinder 2 ′ is also associated with two pairs of rail sections, respectively 51 ′ a, 51 ′ b carried by the front column 10 and 52 ′ a, 52 ′ b carried by the rear column 100.

In addition, each rail section 51, 51 'is slidably mounted, parallel to the axis of the cylinder, on a slide 6, 6' formed on the corresponding projecting part 41, 41 'of the hydraulic block 4. Thus, each section of rail can slide axially between a retracted position for which the rail section 51, 52 has returned to the level of the column 10, 100 corresponding to the cage and an advanced position, shown in phantom in the figure, for which the two sections 51, 52 of each rail 5 extend towards one another in the interval 17 between the two columns 10, 100 of the cage. Thanks to this division of each rail 5 into two sections of limited length, it is possible to place said sections at the level of the projecting parts 41, 41 ′, between the ends thereof and the lateral sides 34 of the chocks, without hampering the vertical displacements of the cylinder.

According to another characteristic of the invention, the rollers 7 for supporting each chock are spaced from the median plane Q thereof a distance greater than the distance between said median plane and the corresponding end of the section of rail so that it does not risk interfering with the movements of the roller 7 linked to the chock, during the height adjustments thereof.

This arrangement is shown in detail in Figure 4 which is a longitudinal sectional view of the rear chocks 30, 30 'placed on the side opposite to the disassembly side of the cylinders.

We see, in fact, that, in this case, each rear chock 30 is supported, on each side of the clamping plane P ₂ , by two rollers spaced apart on either side of the median plane Q of the chock, respectively a external roller 72 placed outside the cage and an internal roller 72 'placed inside, in the interval 17 between the two columns 10, 100. Each roller 72 is mounted at the end of an arm 73 fixed on the side of the chock and extending inward or outward so that the two rollers 72, 72 'are spaced from each other by a distance d greater than the length I of the rail section 52. In this way, the rollers 72, 72 ', which are placed beyond the ends, respectively external 54 and internal 54' of the corresponding rail section 52, do not hinder the vertical movements of the chock 3 when the rail section 52 is moved back to the rolling position.

In this regard, it should be noted that the vertical displacements of the chocks and the axial displacements of the rail sections never occur simultaneously. Therefore, each rail section 51, 52 can be threaded without play between the end face 46 of the projecting part 41, 41 'and the bottom 36 of the notch 33 formed on the lateral side 34 of the chock. The two contacting faces 56 of the rail section 51, 52 and 36 of the chock 3 can cooperate with the guide faces 35, 45 for the lateral holding of the chock and are, for this purpose, provided with plates wear sliding one on the other, on the one hand during the vertical movements of the chock and, on the other hand, during the axial movements of the rail section 51, 52.

Preferably, the front chock 3, 3 ′ placed at the other end of the cylinder 2, on the disassembly side and threaded into the column 10 of the cage is also provided, on each side of the clamping plane P ₂ , with two respectively external 71 and internal 71 'rollers spaced apart by a distance d greater than the length of the corresponding rail section 52. Thus, the two chocks, 3, 30 of each cylinder 2 are identical. However, the front chock 3 could be supported by a single rear roller 71 ', mounted on an arm extending towards the inside of the cage. In their disassembly position shown in phantom in the figure

2, the rail sections are advanced cantilevered and must therefore remain embedded on the slides 6 over a length sufficient to support the weight of the cylinder.

In addition, in this disassembly position, the opposite internal ends 53 ′, 54 ′ of the two sections 51, 52 of the same rail mounted respectively on the two columns 10, 100 of the cage are spaced apart by a free space of width e.

The length I of the rail sections and the spacing d between the support rollers of the chock must therefore be determined, on the one hand to maintain a sufficient embedding length of each section and, on the other hand so that l the spacing of the rollers is greater than the distance e between the ends of two sections of rails so as to allow the disassembly of the cylinder by rolling successively on the two sections, as will be seen below with reference to the diagram in FIG. 5. Of course, all the arrangements which have just been described for the lower cylinder 2 with reference to FIG. 2 are identical for the upper cylinder 2 ', the latter also being associated with two pairs of rail sections, respectively 51' a, 52'a and 51 'b, 52'b. It is advantageous to simultaneously control the sliding of all of the sections of rails placed on the same column, between the retracted rolling position and the advanced disassembly position.

To this end, as shown in FIG. 3, on each side of the clamping plane P ₂ , the two rail sections, respectively lower 51 and upper 51 'are each connected by an arm 81, 81' to a connection plate 8 which extends vertically along the hydraulic block 4 and on which the rod of a jack 82 rests, the body of which is articulated on the hydraulic block 4, the latter being provided, in its central part, with a recess 47 in which extends horizontally the jack 82.

As shown in Figure 4, this connecting device 8 is advantageously provided, in its central part, with a guide plate 83 which extends horizontally over the same length as the rail sections 51 and which slide in a horizontal slide 61, arranged on the hydraulic block 4.

This central slide 61 cooperates with the two slides 6, 6 ′ for guiding the rail sections 51, 51 ′ for the cantilever maintenance of the latter in their advanced disassembly position.

The operation of the device is shown diagrammatically in FIG. 5 which shows the successive sequences of disassembly of the upper cylinder 2 ′, these sequences being, obviously, the same for the lower cylinder 2.

In FIG. 5a, the two working rolls 2, 2 'are in the rolling position of a product M. The spacing of their chocks 3, 3' therefore depends on the thickness of the product and the degree of wear of the cylinders 2, 2 '.

In this position, the rollers 71, 72 of the upper chocks 3'a, 3'b may possibly be at the level of the upper rail sections 51 ', 52'. Indeed, as we have seen, the distance d between the rollers 71, 72 of each chock 3'a, 3'b is greater than the length I of the corresponding rail section 51 ', 52' and the latter it therefore does not oppose the vertical movements of the chock under the action of the adjustment cylinders 42, 43. When the cylinders 2, 2 ′ are worn and need to be replaced, they are moved apart on either side of the product to be laminated M, each at its dismantling level, in the position shown in FIG. 5b. The rollers 71, 72 are then located just above the level of the upper faces of the rail sections 51, 52.

We then advance towards the inside of the cage, in their disassembly position, the rail sections 51, 51 'mounted on the front column 10 of the cage placed on the disassembly side. As indicated, the rolling mill is associated, on this side, with an auxiliary carriage carrying external rails 55 which are placed in the extension of the rail sections 51 ′, in the position shown in FIG. 5c.

Preferably, the sections of rails 52 ′ placed on the side opposite to the dismantling side are slightly moved back so as to be placed below the rear rollers 72 of the corresponding chock 30 ′ of the cylinder 2 ′. By known means mounted on the auxiliary carriage and not shown in the figures, the axial displacement of the cylinder 2 'then carried by its two chocks, the chock before 3' being supported, by its two rollers 71, 71 'respectively on the outer rails 55 and the sections 51 'and the rear chock 30' rolling on the rear sections 52 '. The latter are then advanced into the position shown in FIG. 5d for which the internal ends, facing 53 ′, 54 ′ of the rail sections 51 ′, 52 ′ are separated by a space of length e less than the distance d between the two rollers 72, 72 '.

The rear chock 30 ′ can therefore cross this space by bearing, first on the rear section 52 ′ by its rear roller 72 then on the front section 51 ′ by its front roller 72 ′.

The axial movement of the cylinder 2 'can then continue as indicated in FIG. 5e until the two chocks 3', 30 'rest on the outer rails 55 of the auxiliary carriage. The withdrawal of the lower cylinder 2 is done in the same way, each column being equipped with means for simultaneously controlling the advancement and retreat of the two pairs of rail sections placed respectively at the two disassembly levels. In known manner, the auxiliary carriage can be equipped with two boxes each provided with two pairs of outer rails 55 placed at the two dismantling levels, respectively a free box for the reception of used cylinders and a reserve box comprising two new cylinders which are introduced into the cage by performing the same sequences in reverse order.

However, the invention is obviously not limited to the details of the embodiment which has just been described by way of simple example, equivalent means being able to be used without departing from the protective framework defined by the claims. In particular, it is particularly advantageous to use chocks with offset ears of the type shown in FIGS. 2 to 4, but the invention would also be applicable to a rolling mill equipped with chocks of conventional type as shown in FIG. 1.

On the other hand, only the chocks 30, 30 'placed on the side opposite to the dismantling side must cross the space e between the two sections of each rail and, consequently, be equipped with two separated rollers 72, 72'. To simplify, the chocks 3, 3 ′ placed on the dismantling side could comprise a single roller sufficiently spaced from the median plane Q to allow the vertical movement of the chock when the corresponding rail sections are in their rolling position.

The reference signs inserted after the technical characteristics mentioned in the claims have the sole purpose of facilitating the understanding of the latter and in no way limit their scope.

Claims

CLAIMS 1. Device for dismantling rolls for a rolling mill comprising a holding cage (1) having two spaced apart columns (10,100) and at least two working rolls, respectively lower (2) and upper (2 '), defining an air gap of passage of a flat product (M) along a rolling plane (Pi), each cylinder (2, 2 ') being rotatably mounted around its axis on two holding chocks (3, 30, 3', 30 ') centered each on a median plane (Q) orthogonal to the axis of the cylinder and threaded respectively in two windows (11) each formed between two uprights (12) of each column (10, 100), each window (11) being provided with faces (45) for sliding guide of said chocks parallel to a clamping plane (P ₂ ) passing substantially through the axes of the rolls, said rolling mill being equipped with a device for dismantling the rolls by translation, successively, on at least one pair of rails internal (5) parallel to the axes of cylinders and extending respectively, on each side of the clamping plane (P ₂ ), between the corresponding uprights of the two columns (10, 100) of the cage (1), and at least one pair of external rails (55) s 'extending outside the cage (1), at least on one disassembly side, each in the extension of an internal rail (5), the two chocks of at least one cylinder (2) being provided with movable support members (7) on said internal (5) and external (55) rails, characterized in that, on each side of the clamping plane (P ₂ ), each internal rail (5) consists of two sections (51, 52) each extending, over a limited length, between two ends, respectively internal (53 ', 54') and external (53, 54), and mounted sliding, respectively, on the two columns (10, 100 ) of the cage (1), parallel to the axis of the cylinder, that the rolling mill comprises means (82) for controlling the sliding of the two sections (51, 52) of each internal rail (5) e ntre a rolling position for which each section (51, 52) is moved back outside the interval (17) between the two columns (10, 100), and a disassembly position of the cylinder (2) for which the two sections (51, 52) are advanced towards each other, in the interval (17) between the two columns (10, 100), the internal ends (53 ', 54') of said sections (51, 52) being separated by a free space (e), that each movable support member (71) of a chock (3) is moved away from the median plane (Q) thereof, by a distance greater than the distance between said median plane (Q) and the corresponding end of said section of rail, when the latter is in the position rolling and that at least the chock (30) holding the end of the cylinder (2) opposite the dismantling side is equipped on each side of the clamping plane (P ₂ ), with two movable support members (72, 72 ') spaced from each other, by a distance (d) greater than the length (e) of the existing free space, in the disassembly position of the cylinder, between the internal ends, in opposite (53 ', 54'), of the two sections (51, 52) of internal rail (5).

2. Device according to claim 1, characterized in that the two chocks (3, 30) of each cylinder (2) are each provided, on either side of the clamping plane (P ₂ ), with a pair mobile support members (71, 71 '), (72, 72') spaced from each other, in the axial direction by a distance (d) greater than the length (I) of the section of corresponding rail (51, 52).

3. Device according to one of claims 1 and 2, characterized in that the two sections of rails (51), (52) mounted on the same column (10), (100) of the cage, on both sides and d 'other of the clamping plane (P ₂ ), are joined together by connecting means (8) and associated with means (82) for controlling the simultaneous sliding of the two sections (51), (52), from the position of rolling to the dismantling position, and vice versa.

4. Device according to one of the preceding claims, for the simultaneous disassembly of the two working rolls (2, 2 '), bearing on one another, characterized in that it comprises two pairs of sections of rails (51, 52) mounted respectively on the two columns (10, 100) of the cage, at the same level of disassembly of a first cylinder (2) on which the second cylinder (2 ') is supported.

5. Device according to one of claims 1 to 3, characterized in that it comprises four pairs of rail sections (51, 52), (51 ', 52') mounted respectively, at two levels of disassembly, on the two columns (10, 100) of the cage (1) for which the two cylinders (2, 2 ') are spaced on either side of the product (M) during rolling, so as to form, at each level, a pair of internal rails (5, 5 ') extending respectively on either side of the clamping plane (Pi).

6. Device according to one of the preceding claims, characterized in that the movable support members of the chocks (3, 30) are rollers (71, 72) for rolling on the rail sections (51), (52 ).

7. Device according to one of claims 1 to 5, characterized in that the movable support members of the chocks are sliding parts on the rail sections.

8. Device according to one of the preceding claims, characterized in that the rolling mill is equipped with C hydraulic blocks comprising, on either side of the rolling plane (Pi), two projecting parts (41, 41 ' ) at the ends of which are provided faces (45) for lateral guidance of the working chocks (3) which are each provided with two support ears (31) for adjusting the height of the chock, and that said ears support (31) are offset towards the rolling plane (Pi) and engage in a central notch (42) of each hydraulic block (4) formed between the projecting parts (41, 41 ') thereof.

9. Device according to claim 8, characterized in that the rail sections (51, 52) mounted on each column (10, 100), on either side of the clamping plane (P ₂ ) for the support of each cylinder (2, 2 ') are arranged along the ends of the projecting parts (41, 41') of the hydraulic blocks (4) and are housed in notches (33) formed over part of the height on each lateral side (34) of a chock (4), retaining on said lateral side (34) and on the end of the projecting part (41, 41 ') guide faces (35, 45) sliding one on the other and having a height (h ₂ ) compatible with the possibilities of adjusting the level of the chock (3).

10. Device according to claim 9, characterized in that each rail section (51, 52) is slidably mounted axially between the end of the projecting part (41, 41 ') of the hydraulic block (4) and the bottom (36) of the notch (33) formed on the lateral side (34) of the chock (3), said bottom (36) and the corresponding face (46) of the rail (51, 52) being provided with plates wear sliding one on the other, on the one hand in the axial direction during movement of the rail section (51, 52) and, on the other hand, in the vertical direction during adjustments level of the chock, so as to constitute an additional means for lateral retention of the chock (3).

11. Device according to one of the preceding claim, characterized in that each movable support member (71, 72) of a chock (3, 30) is mounted at the end of an arm (73) fixed on the chock and extending axially over a length such that said support member (71, 72) is spaced from the median plane Q of the chock (3) by a distance greater than the distance between said median plane (Q) and the corresponding end (53, 54) of the rail section (51, 52).

12. Device according to one of claims 10 and 11, characterized in that each rail section is slidably mounted axially on a slide (6) formed on the end of the projecting part (41, 41 ') of the block hydraulic and that, in the advanced disassembly position, the slide (6) associated with each section of rail (51, 52) remains engaged in said protruding part (41, 41 ') over a sufficient installation length for the maintenance overhanging the rail section (51, 52) under the load of the cylinder (2).

13. Device according to claim 12, comprising, on each column (10, 100) of the cage (1), two pairs of rail sections (51, 51 '), (52, 52') placed at two levels of disassembly , respectively, of the two working cylinders (2, 2 '), characterized in that the two rail sections (51, 51') (52, 52 ') placed on each column (10, 100) and on each side of the clamping plane (P ₂ ) are secured by a connecting member (8) on which is supported a first element of an actuator (82) for controlling axial movement, the second element of which is supported on the column (10, 100 ) and that the two jacks (82) placed respectively on either side of the clamping plane (P ₂ ) are actuated in synchronism for controlling the simultaneous axial movement of the rail sections of the two pairs (51, 51 ') ( 52, 52 ').

14. Method for replacing cylinders in a rolling mill equipped with a device according to one of the preceding claims, associated with a replacement carriage placed on a side for dismantling the cage, in which each rail (5) for dismantling a cylinder consists of two sections (51, 52) slidably mounted parallel to the axis of the cylinder (2, 2 ') each on a column (10, 100) of the cage, characterized in that, after having placed each cylinder (2, 2 ') at its disassembly level, the sliding, towards the inside of the cage, of the sections of internal rails (51) mounted on the front column (10) placed on the disassembly side is controlled, the replacement carriage is brought to this column (10) which is provided with external rails (55) which is placed in the extension of the sections (51) thus advanced, then the translation of the cylinder to be replaced (2, 2 ') is controlled which rests on the two pairs of sections of rails (51, 52) then the sections (52) placed on the rear column (100) are advanced and the advancement of the cylinder is then continued including the rear chock ( 30) is supported successively on the rear sections (52) then before (51) by its two support members spaced apart, crossing the free space between said sections, until the worn cylinder rests on the replacement carriage and, by reverse operations, a new cylinder is introduced into the cage, then fa it slide the rail sections (51, 52) out of the cage to replace them in the rolling position, each in the grip of a column (10, 100).